Printed circuit board support

ABSTRACT

A printed circuit board conveying system is provided comprising a printed circuit board conveyor and a printed circuit board support. The printed circuit board support is positioned to support a major portion of the printed circuit board between opposite lateral edge portions of the board and comprises a support base, a spacer, and a spacer securement. A printed circuit board processing system including the conveying system is also provided. The conveying system couples a printed circuit board loader to a stencil printer, a pick and place machine, and a reflow oven.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/375,807, filed Feb. 27, 2003, which is a division of application Ser.No. 09/704,294, filed Nov. 1, 2000, now U.S. Pat. No. 6,631,798. Thisapplication is further related to application Ser. No. 10/375,456, filedFeb. 27, 2003, Ser. No. 10/375,275, filed Feb. 27, 2003, now U.S. Pat.No. 6,749,054, and Ser. No. 10/375,818, filed Feb. 27, 2003, whichapplications also claim priority to application Ser. No. 09/704,294,filed Nov. 1, 2000, now U.S. Pat. No. 6,631,798.

BACKGROUND OF THE INVENTION

The present invention relates to printed circuit board handling andmanufacturing processes and, more particularly, to an improved printedcircuit board support, printed circuit board conveying system, andprinted circuit board processing system.

Conventional printed circuit board processing systems, e.g., SMT(surface mount technology) manufacturing systems, typically utilize aconveyor system to move a printed circuit board from station to stationwithin the system. Often, the printed circuit board is supported or heldin a manner that is insufficient to prevent the board from warping,twisting, or bending during processing. Accordingly, there is a need inthe art of printed circuit board handling and processing for an improvedprinted circuit board support.

BRIEF SUMMARY OF THE INVENTION

This need is met by the present invention wherein an improved printedcircuit board support, an improved printed circuit board conveyingsystem, and an improved printed circuit board processing system areprovided. In accordance with one embodiment of the present invention, aprinted circuit board support is provided comprising a support base, aspacer, and a spacer securement. The support base defines a supportsurface. The spacer engages the support surface. The spacer securementincludes a projection and a recess. The projection adjoins one of thesupport base and the spacer. The recess is formed in the other of thesupport base and the spacer. The projection extends into the recess andthe projection and the recess are configured such that the extension ofthe projection into the recess limits movement of the spacer relative toa plane parallel to the support surface.

The printed circuit board support may comprise two or more spacersecurements. The projection may comprise a substantially cylindrical pinand the recess may comprise a cylindrical recess having a diameterslightly larger than the pin. The spacer may define an upper spacersurface spaced from and substantially parallel to the support surface.

In accordance with another embodiment of the present invention, aprinted circuit board support assembly is provided comprising a supportbase and a plurality of spacers. The support base defines a supportsurface and at least one recess formed therein. The recess defines anopening on the support surface. The plurality of spacers definerespective upper spacer surfaces and opposite spacer surfaces. Thespacers define a range of respective thickness dimensions betweenrespective ones of the spacer surfaces and corresponding ones of theopposite spacer surfaces. Each of the spacers includes at least oneprojection extending from the opposite spacer surface. The respectiveprojections and the recess formed in the support base are sized toenable extension of the respective projections into the recess and tolimit movement of the spacer relative to a plane parallel to the supportsurface.

In accordance with yet another embodiment of the present invention, aprinted circuit board support is provided comprising a support base. Thesupport base defines a support surface, a leading edge, a trailing edge,and a pair of lateral edges. The support base also defines a cut-outformed therein. The cut-out is positioned between the pair of lateraledges and extends from the leading edge in the direction of the trailingedge to a position between the leading edge and the trailing edge.

The leading edge, the trailing edge, and the pair of lateral edges maybe defined in a substantially planar surface of the support base. Thecut-out may be formed in the support surface of the support base. Theprinted circuit board support may further comprise a spacer and a spacersecurement. The spacer engaging the support surface and including anadditional cut out formed therein and the spacer securement arranged tosecure the spacer to the support surface with the additional cut-outaligned with the cut-out formed in the support base. The additionalcut-out and the cut-out in the support base may be coextensive. Theadditional cut out may be formed in an upper spacer surface of thespacer.

In accordance with yet another embodiment of the present invention, aprinted circuit board support is provided comprising a support basedefining a support surface. A base extension assembly is secured to thesupport base and is arranged to define a variable extension assemblyheight dimension and at least a portion of a height dimension of theprinted circuit board support, wherein variation of the variableextension assembly height dimension results in variation of the heightdimension of the printed circuit board support.

The base extension assembly may be further arranged such that theextension assembly height dimension varies in response to a forceapplied to the support surface. The base extension assembly comprises aspring-loaded extension including a spring arranged to compress inresponse to a force applied to the support surface. The base extensionassembly may comprise a viscously damped extension arranged to compressin response to a force applied to the support surface. The baseextension assembly may comprise a pair of support legs. Each of the pairof support legs may be arranged such that the extension assembly heightdimension varies in response to a force applied to the support surface.

In accordance with yet another embodiment of the present invention, aprinted circuit board support is provided comprising a support base, abase extension, and a magnetic source. The support base defines asupport surface and a lower surface. The base extension is secured tothe support base and is arranged to define at least a portion of aheight dimension of the printed circuit board support. A magnetic sourceis secured to the base extension and is positioned such that the lowersurface of the support base is arranged to secure the printed circuitboard support to an object under magnetic force. The magnetic source maycomprise a permanent magnet and may be secured within a cavity formed inthe lower surface of the support base.

In accordance with yet another embodiment of the present invention, aprinted circuit board conveying system is provided comprising a pair ofconveyor rails and a printed circuit board support. The pair of conveyorrails are positioned to engage opposite lateral edge portions of aprinted circuit board and are configured to convey the printed circuitboard along a conveyor path. The printed circuit board support ispositioned to support a portion of the printed circuit board between thelateral edge portions. The printed circuit board support comprises asupport base defining a support surface, a spacer engaging the supportsurface, and a spacer securement including a projection and a recess.The projection adjoins one of the support base and the spacer. Therecess is formed in the other of the support base and the spacer. Theprojection extends into the recess. The projection and the recess areconfigured such that the extension of the projection into the recesslimits movement of the spacer relative to a plane parallel to thesupport surface. A thickness dimension of the spacer is selected toenable engagement of the spacer with the printed circuit board.

In accordance with yet another embodiment of the present invention, aprinted circuit board conveying system is provided comprising a pair ofconveyor rails, a printed circuit board support, and a stop mechanism.The pair of conveyor rails are positioned to engage opposite lateraledge portions of a printed circuit board and are configured to conveythe printed circuit board along a conveyor path. The printed circuitboard support is positioned to support a portion of the printed circuitboard between the lateral edge portions and comprises a support base.The support base defines a support surface, a leading edge, a trailingedge, a pair of lateral edges, and a cut-out formed therein. The cut-outis positioned between the pair of lateral edges and extends from theleading edge in the direction of the trailing edge to a position betweenthe leading edge and the trailing edge. The stop mechanism is positionedto engage the printed circuit board support at a point within thecut-out. The stop mechanism may include an actuator and a pin and may beconfigured to selectively extend and retract the pin to and from aposition engaging the printed circuit board support at the point withinthe cut-out.

In accordance with yet another embodiment of the present invention, aprinted circuit board conveying system is provided comprising a pair ofconveyor rails and a printed circuit board support. The pair of conveyorrails are positioned to engage opposite lateral edge portions of aprinted circuit board and configured to convey the printed circuit boardalong a conveyor path. The printed circuit board support is positionedto support a portion of the printed circuit board between the lateraledge portions and comprises a support base and a base extensionassembly. The support base defines a support surface. The base extensionassembly is secured to the support base and is arranged to define avariable extension assembly height dimension and at least a portion of aheight dimension of the printed circuit board support. Variation of thevariable extension assembly height dimension results in variation of theheight dimension of the printed circuit board support. The baseextension assembly is configured such that the height dimension of theprinted circuit board support permits engagement of the support surfacewith the printed circuit board.

In accordance with yet another embodiment of the present invention, aprinted circuit board conveying system is provided comprising a pair ofconveyor rails, a conveyor platform, and a printed circuit boardsupport. The pair of conveyor rails are positioned to engage oppositelateral edge portions of a printed circuit board and are configured toconvey the printed circuit board along a conveyor path. The printedcircuit board support is positioned to support a portion of the printedcircuit board between the lateral edge portions. The printed circuitboard support comprises a magnetic source secured to the base extensionassembly and positioned such that the lower surface of the support basesecures the printed circuit board support to the conveyor platform undermagnetic force, wherein the base extension assembly is configured suchthat the height dimension of the printed circuit board support permitsengagement of the support surface with the printed circuit board.

In accordance with yet another embodiment of the present invention, aprinted circuit board processing system is provided. The system includesa printed circuit board conveying system coupling a printed circuitboard loader to a stencil printer, a pick and place machine, and areflow oven. The printed circuit board conveying system comprises a pairof conveyor rails and a printed circuit board support according to thepresent invention.

In accordance with yet another embodiment of the present invention, amethod of conveying a printed circuit board in a printed circuit boardconveying system is provided. The conveying system is provided inaccordance with the present invention and the conveying method comprisesthe steps of selecting one of the plurality of spacers as a function ofits thickness and a thickness profile of the printed circuit boardengaged by the pair of conveyor rails; installing the selected spacer byextending at least one of the respective projections into the recess;and engaging an upper spacer surface of the selected spacer with theprinted circuit board.

In accordance with yet another embodiment of the present invention, amethod of conveying a printed circuit board in a printed circuit boardconveying system is provided. The conveying system is provided inaccordance with the present invention and the conveying method comprisesthe steps of engaging the support surface of the support base with theprinted circuit board engaged by the pair of conveyor rails and varyingthe height dimension of the base extension assembly as a function of athickness profile of the printed circuit board.

In accordance with yet another embodiment of the present invention, amethod of processing a printed circuit board in a processing systemincluding a printed circuit board conveying system coupling a printedcircuit board loader to a stencil printer, a pick and place machine, anda reflow oven is provided. The printed circuit board conveying system isprovided in accordance with the present invention and the processingmethod comprises the steps of selecting one of the plurality of spacersas a function of its thickness and a thickness profile of the printedcircuit board engaged by the pair of conveyor rails, installing theselected spacer by extending at least one of the respective projectionsinto the recess, and engaging an upper spacer surface of the selectedspacer with the printed circuit board within the operating envelope ofthe pick and place machine.

In accordance with yet another embodiment of the present invention, amethod of processing a printed circuit board in a processing systemincluding a printed circuit board conveying system coupling a printedcircuit board loader to a stencil printer, a pick and place machine, anda reflow oven is provided. The printed circuit board conveying system isprovided in accordance with the present invention and the processingmethod comprises the steps of engaging the support surface of thesupport base with the printed circuit board engaged by the pair ofconveyor rails within the operating envelope of the pick and placemachine and varying the height dimension of the base extension assemblyas a function of a thickness profile of the printed circuit board.

Accordingly, it is an object of the present invention to provide animproved printed circuit board support, an improved printed circuitboard conveying system, and an improved printed circuit board processingsystem. Other objects of the present invention will be apparent in lightof the description of the invention embodied herein.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The following detailed description of the preferred embodiments of thepresent invention can be best understood when read in conjunction withthe following drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1 is an illustration of a printed circuit board support accordingto one embodiment of the present invention;

FIG. 2 is an illustration of a printed circuit board support accordingto another embodiment of the present invention;

FIG. 3 is an illustration of a printed circuit board support accordingto yet another embodiment of the present invention;

FIG. 4 is an illustration of a printed circuit board conveying systemaccording to the present invention; and

FIG. 5 is an illustration of a printed circuit board processing system.

DETAILED DESCRIPTION

Referring now to FIGS. 1–5 a printed circuit board support 5, printedcircuit board conveying system 60, and a printed circuit boardprocessing system 70 according to the present invention are illustrated.The printed circuit board support 5 illustrated in FIG. 1 comprises asupport base 10 defining a support surface 12. A base extension assembly20 is secured to the support base 10. The base extension assembly 20 maybe secured to the support base 10 by forming the extension assembly 20and the support base 10 as a single integral piece or by coupling twoseparate pieces mechanically, adhesively, magnetically, or otherwise.

The support base 10 defines a leading edge 14, a trailing edge 16, and apair of lateral edges 18. As is illustrated in FIG. 1, the leading edge14, the trailing edge 16, and the pair of lateral edges 18 are definedin a substantially planar support surface 12 of the support base 10. Inthe illustrated embodiment, the base extension assembly 20 comprises apair of support legs 22, 24.

According to one embodiment of the present invention, a cut-out 15 isformed in the support base 10. The cut-out 15 is positioned between thepair of lateral edges 18 and extends from the leading edge 14 in thedirection of the trailing edge 16 to a position between the leading edge14 and the trailing edge 16. In the illustrated embodiment, the cut-out15 is formed in the support surface 12 of the support base 10. Thepurpose of the cut-out 15 is illustrated in further detail herein withreference to the function of the conveying and processing systems of thepresent invention.

Referring specifically to FIGS. 1 and 2, the printed circuit boardsupport 5 may further comprise a pair of permanent magnets 30 securedwithin respective cavities in each of the support legs 22, 24 of thebase extension 20. The magnets 30 are positioned such that the lowersurface of the support base 10 is arranged to secure the printed circuitboard support 5 to a conveyor platform or other object 40 under magneticforce. Alternative magnetic sources 30, e.g., electromagnets, may beprovided without departing from the scope of the present invention.

The base extension assembly 20 may comprise a single molded piece withor without attachments or, as is illustrated in FIG. 3, may comprise acompound assembly arranged to define a variable height dimension a ofthe extension assembly 20 and at least a portion of a height dimension bof the printed circuit board support 5. As will be appreciated by thosepracticing the present invention, variation of the variable extensionassembly height dimension a results in variation of the height dimensionb of the printed circuit board support 5.

The extension assembly 20 illustrated in FIG. 3 may comprise a springarranged to compress in response to a force applied to the supportsurface 12, a viscously damped extension arranged to compress inresponse to a force applied to the support surface 12, or any othercomponents arranged to enable variation of the height dimension a of theextension assembly 20. The variation of the height dimension a may be inresponse to a force applied to the support surface 12 or may be a resultof selective control of the height dimension a independent of the forceapplied to the support surface 12. In the illustrated embodiment, eachof the pair of support legs 22, 24 are arranged, in the manner describedherein, such that the extension assembly height dimension is variable.

Referring further to FIG. 2, an additional embodiment of the presentinvention is illustrated. A spacer 50 is provided in engagement with thesupport surface 12. A spacer securement 52 includes a recess 54 in theform of a cylindrical bore and a projection 56 in the form of a pin. Inthe illustrated embodiment, the pin 56 is mounted to or formedintegrally with the spacer 50 and the recess 54 is formed in the supportbase 10. It is contemplated, however, that the pin 56 may be mounted tothe support base 10 and the recess 54 may be formed in the spacer 50.

In the engaged state, the projection 56 extends into the recess 54 andthe projection 56 and the recess 54 are configured such that theextension of the projection 56 into the recess 54 limits movement of thespacer 50 relative to a plane parallel to the support surface 12. As isillustrated in FIG. 2, the printed circuit board support 5 may compriseat least two spacer securements 52.

The spacer 50 functions to provide an upper spacer surface 58 spacedfrom and substantially parallel to the support surface 12. As clearlyillustrated in FIGS. 2 and 4, the upper spacer surface 58 is sized andconfigured to support and engage a major portion of a printed circuitboard 80. Most preferably a plurality of spacers of differentthicknesses are made available for engagement with the support base 10.In this manner, the printed circuit board support 5 may be configured tosupport a variety of printed circuit boards of varying thicknessprofiles.

In the embodiment illustrated in FIG. 2, the spacer 50 engaging thesupport surface 12 includes an additional cut out 55 formed therein. Thespacer securements 52 are arranged to secure the spacer 50 to thesupport surface 12 with the additional cut-out 55 aligned with thecut-out 15 formed in the support base 10. Typically, the additionalcut-out 55 and the cut-out 15 in the support base 10 are coextensive,i.e., they have substantially the same spatial scope or boundaries.Moreover, as clearly illustrated in FIGS. 1–3, the cut-out 15 transectsthe thickness of the support base 10 and, as clearly illustrated in FIG.2, the additional cut-out 55 transects the thickness of the spacer 50.The additional cut out 55 is formed in an upper spacer surface 58 of thespacer 50. The upper surface 58 of the spacer 50 and the support surface12 collectively define a pair of supportive extensions 25 which provideadditional support for printed circuit boards that extend across thecut-out 15 and the additional cut-out 55.

Referring now to FIGS. 4 and 5, a printed circuit board conveyingsystem, a printed circuit board processing system, and their manners ofoperation are described. A printed circuit board conveying system 60 isincorporated within the processing system 70 and includes a conveyor 62coupling a printed circuit board loader 72 to a stencil printer 74, apick and place machine 76, and a reflow oven 78. The printed circuitboard conveying system 60 comprises a pair of conveyor rails 64positioned to engage opposite lateral edge portions 82 of a printedcircuit board 80 and is configured to convey the printed circuit board80 along a conveyor path, as indicated by directional arrow 66. Aprinted circuit board support 5 according to the present invention ispositioned to support a major portion of the printed circuit board 80between the lateral edge portions 82 within an operating envelope of thepick and place machine 76. It is contemplated by the present inventionthat the printed circuit board support 5 may be positioned to support amajor portion of the printed circuit board 80 within the respectiveoperating envelopes of other components of the processing system 70 aswell.

A stop mechanism 90 is illustrated in FIG. 4, and includes an actuator92 and a pin 94. The stop mechanism 90 is configured to selectivelyextend and retract the pin 94 to and from a position engaging theprinted circuit board support 5 at a point within the cut-out 15. Inthis manner, the stop mechanism 90 may be utilized to control themovement of selected printed circuit board supports 5 along the conveyorpath.

In operation, one of a plurality of spacers 50 (See FIG. 2) havingdifferent thicknesses is selected depending upon the thickness profileof the printed circuit board 80 engaged by the pair of conveyor rails64. More specifically, the spacer 50 having a thickness most suitablefor optimum supportive engagement of the printed circuit board 80 by theprinted circuit board support 5 is selected. The selected spacer 50 isinstalled by extending or positioning the respective projections 56 intothe corresponding recesses 54. The upper spacer surface 58 of theselected spacer 50 is then utilized to engage the printed circuit board80 within the operating envelope of the pick and place machine 76.Alternatively, the spacer 50 may be eliminated and the base extensionassembly 20 may be arranged to define a variable extension assemblyheight dimension a, as discussed herein with reference to FIG. 3, andthe height dimension of the base extension assembly 20 may be varied asa function of a thickness profile of the printed circuit board 80. Inwhich case the upper surface 12 will engage the printed circuit board80. It is contemplated that the variable height base extension assembly20 and the spacers 50 may be utilized in a cooperative relationship in asingle embodiment of the present invention.

Having described the invention in detail and by reference to preferredembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of theinvention defined in the appended claims. More specifically, althoughsome aspects of the present invention are identified herein as preferredor particularly advantageous, it is contemplated that the presentinvention is not necessarily limited to these preferred aspects of theinvention.

1. A printed circuit board conveying system comprising: a conveyorconfigured to convey a printed circuit board along a conveyor path; anda printed circuit board support positioned to support a major portion ofsaid printed circuit board between opposite lateral edge portions ofsaid printed circuit board, said printed circuit board supportcomprising a support base, a spacer, and a spacer securement, whereinsaid support base defines a support surface, said spacer securementincludes a projection and a recess, said projection is mounted to orformed integrally with one of said support base and said spacer, saidrecess is formed in the other of said support base and said spacer, saidprojection extends into said recess, and said projection and said recessare configured such that said extension of said projection into saidrecess limits movement of said spacer relative to a plane parallel tosaid support surface.
 2. A printed circuit board conveying system asclaimed in claim 1 wherein said projection is mounted to or formedintegrally with said spacer and said recess is formed in said supportbase.
 3. A printed circuit board conveying system as claimed in claim 1wherein said printed circuit board support comprises at least two spacersecurements.
 4. A printed circuit board conveying system as claimed inclaim 1 wherein said projection comprises a substantially cylindricalpin and said recess comprises a cylindrical recess having a diameterslightly larger than said pin.
 5. A printed circuit board conveyingsystem as claimed in claim 1 wherein said spacer defines an upper spacersurface spaced from and substantially parallel to said support surface.6. A printed circuit board conveying system as claimed in claim 5wherein said upper spacer surface is sized and configured to support andengage a major portion of said printed circuit board.
 7. A printedcircuit board conveying system comprising: a conveyor configured toconvey a printed circuit board along a conveyor path; a printed circuitboard support positioned to support a major portion of said printedcircuit board between opposite lateral edge portions of said printedcircuit board, said printed circuit board support comprising a supportbase wherein said support base defines a support surface, said supportbase defines a leading edge, a trailing edge, and a pair of lateraledges, said support base defines a cut-out formed therein, and saidcut-out is positioned between said opposite lateral edge portions andextends from said leading edge in the direction of said trailing edge toa position between said leading edge and said trailing edge, whereinsaid cut-out transects the thickness of said support base; and a stopmechanism positioned to engage said printed circuit board support at apoint within said cut-out.
 8. A printed circuit board conveying systemas claimed in claim 7 wherein said leading edge, said trailing edge, andsaid pair of lateral edges are defined in a substantially planar surfaceof said support base.
 9. A printed circuit board conveying system asclaimed in claim 7 wherein said cut-out is formed in said supportsurface of said support base.
 10. A printed circuit board conveyingsystem as claimed in claim 7 wherein said printed circuit board supportfurther comprises: a spacer including an additional cut out formedtherein, wherein said additional cut-out transects the thickness of saidspacer; and a spacer securement arranged to secure said spacer to saidsupport surface with said additional cut-out aligned with said cut-outformed in said support base.
 11. A printed circuit board conveyingsystem as claimed in claim 10 wherein said additional cut-out and saidcut-out in said support base are coextensive.
 12. A printed circuitboard conveying system as claimed in claim 10 wherein said additionalcut-out is formed in an upper spacer surface of said spacer.
 13. Aprinted circuit board conveying system as claimed in claim 7 whereinsaid stop mechanism includes an actuator and a pin and is configured toselectively extend and retract said pin to and from a position engagingsaid printed circuit board support at said point within said cut-out.14. A printed circuit board processing system including a printedcircuit board conveying system coupling a printed circuit board loaderto a stencil printer, a pick and place machine, and a reflow oven,wherein said printed circuit board conveying system comprises: aconveyor rail configured to convey a printed circuit board along aconveyor path; and a printed circuit board support positioned to supporta major portion of said printed circuit board between opposite lateraledge portions of said printed circuit board within an operating envelopeof said pick and place machine, said printed circuit board supportcomprising a support base, a spacer, and a spacer securement, whereinsaid support base defines a support surface, said spacer securementincludes a projection and a recess, said projection is mounted to orformed integrally with one of said support base and said spacer, saidrecess is formed in the other of said support base and said spacer, saidprojection extends into said recess, and said projection and said recessare configured such that said extension of said projection into saidrecess limits movement of said spacer relative to a plane parallel tosaid support surface.
 15. A printed circuit board processing systemincluding a printed circuit board conveying system coupling a printedcircuit board loader to a stencil printer, a pick and place machine, anda reflow oven, wherein said printed circuit board conveying systemcomprises: a conveyor configured to convey a printed circuit board alonga conveyor path; a printed circuit board support positioned to support amajor portion of said printed circuit board between opposite lateraledge portions of said printed circuit board, said printed circuit boardsupport comprising a support base wherein said support base defines asupport surface, said support base defines a leading edge, a trailingedge, and a pair of lateral edges, said support base defines a cut-outformed therein, and said cut-out is positioned between said oppositelateral edge portions and extends from said leading edge in thedirection of said trailing edge to a position between said leading edgeand said trailing edge, wherein said cut-out transects the thickness ofsaid support base; and a stop mechanism positioned to engage saidprinted circuit board support at a point within said cut-out.